The cutting chain of a chain saw, eventually, will become loose on the chain saw's guide bar after use because of factors, such as wear, that result in elongation of the chain. Several chain saw constructions and associated methods exist to move the guide bar longitudinally away from the drive sprocket of the chain saw to remove slack from the cutting chain and apply the requisite tension to the cutting chain. This ensures that the links of the cutting chain remain snuggly seated in a peripheral channel in the guide bar.
A number of tensioning arrangements and associated methods for adjusting the tension of the cutting chain on the guide bar are known. Typically, retaining assemblies are provided for the tensioning arrangements. The retaining assemblies function so as to hold the guide bars in place. When it is necessary to reposition the guide bar and adjust the tension of the cutting chain, the retaining assembly is loosened so that the guide bar can be moved longitudinally from the drive sprocket to increase the tension in the cutting chain. Thereafter, the retaining assembly is retightened to secure the guide bar in its adjusted position. In some instances, separate tools are required to loosen and tighten the retaining assemblies. In other cases the retaining assemblies include means for their loosening and tightening and separate tools are not required. Additionally, in certain constructions and associated methods, screws, hydraulic pistons or eccentric working parts are integrated into the chain saw and are employed to, essentially, automatically move the guide bar and increase the tension in the cutting chain when the retaining assembly is loosened. In other instances, the guide bar is manually repositioned by the operator grasping and moving the guide bar to its adjusted position.